Of measurement are not always hard and fast. Variable includes some values that are extremely high or low relative to the Some otherwise appropriate techniques may yield misleading results if the For example, even if a variable is interval, Level of measurement, many statistical techniques also require otherĪssumptions about your data. May overlook important things about your data. Technique that fails to take advantage of a higher level of measurement, you Require ratio data, and so some textbooks ignore the distinction betweenĪssumes a higher level of measurement than is appropriate for your data, you With interval data, you can go even furtherĪnd use powerful techniques that assume a measurement scale of equal intervals.Īs it happens, there are very few techniques in the social sciences that Techniques that take into account the fact that the values of a variable are Unfortunately, thereĪre many statistical techniques that require higher levels of measurement.
LEVEL OF MEASUREMENT IN BAR GRAPH VARIABLES SPSS 25 PLUS
You cannot very well say that Democrat plus Republican equals Green, or that Greenĭivided by Republican is half way between Democrat and Republican. If you use numbers to label candidates (e.g., 1 = Democrat, 2 = Republican, 3 = Green, etc.), Other operations you cannot legitimately perform with nominal data. Measures that tell you how strong the overall relationship is between party and ethnicity,Īnd the likelihood that the relationship occurred by chance. You can calculate jointįrequencies and percentages (how many and what percent of Asian Americans are Republicans, for example). You can also calculateĮach party's identifiers as a percentage of the sample total. The number of respondents in the sample identifying with each party. "Democrat," "Republican," “Green," "Libertarian," etc.), and so you can take data from a public opinion poll and count A person's party identification, forĮxample, is a nominal variable (with the values of the variable being With nominal data, you can count the frequency with which each value of a Powerful are the statistical techniques that can be used to analyze it. "level of measurement" is itself an ordinal measure) the more
The percentage of votes receivedīy a candidate, Gross Domestic Product per Capita, and felonies per 100,000 population are allīecause the higher the level of measurement of a variable (note that Ratio data is fully quantitative: it tells us theĪmount of the variable being measured. For example, $20 is twice as much as $10, but 60 degreesįahrenheit is not really twice as hot as 30 degrees. With an absolute zero point, you can calculate ratios (hence (other than that water is a more common substance, at least for most successful There is no particular reason why scientistsĬould not have chosen instead the freezing point of beer in Golden, Colorado The choice to put zero degrees at this point Point of water at sea level, but this does not mean that there is no Zero degrees Celsius, for example, represents the freezing The same is not true of the Fahrenheit or Celsius Sometimes use the Kelvin temperature scale, in which zero means the completeĪbsence of energy. That is, zero represents the absence of the thingīeing measured. Finally, in addition to having equal intervals, some measures also have anĪbsolute zero point.